It took me 20 hours to get to level 58...
WITH heirlooms and a guided path.
To me honest opinion I am thinking the amount of experience given should be buffed a bit. 15% or so. I can't imagine how shitty the experience is as a new player with zero heirlooms. They will unsub before getting to max lol.
I love how the scaling works and I do like the experience is slowed a little. But I think Blizzard went a little too far. It's not fine tuned at all yet. The amount of experience given should be higher.